A circuit and method provide a charge sharing function during skewed data
bus conditions in an integrated circuit memory. The charge sharing
circuit includes two additional circuit blocks, one coupled to each of
the capacitive lines in the charge-sharing line set, to provide the
charge recycling feature. An extra clock signal is active one cycle early
during a first clock period to trigger an extra drive circuit to generate
a voltage differential on a first capacitive line that is similar to the
voltage level generated when real data is being propagated. The presence
of an extra voltage signal on the first capacitive line takes place
earlier than what would normally happen and allows for proper charge
sharing between a second capacitive line and the first capacitive line.
Also, there is an additional control signal associated with a last clock
period following normal non-skewed charge sharing. The additional control
signal triggers a reference read circuit to generate data and a voltage
on the first capacitive lines similar to the voltage present during real
data for proper charge sharing. The additional read and drive circuit
blocks are partial copies of the normal read and drive circuits so that a
matching voltage can be generated on the appropriate capacitive signal
lines.